Flux composition, solder composition, and electronic substrate

Abstract

To provide a flux composition which can sufficiently suppress occurrence of a solder ball, even if a solder alloy containing bismuth or indium is used.SOLUTION: A flux composition contains (A) a resin, (B) an activator, and (C) an antioxidant, wherein the component (C) contains (C1) a compound having a carbon double bond or a hindered phenol structure in one molecule.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a flux composition, a solder composition, and an electronic board. [Background technology]

[0002] The solder composition is a mixture of solder powder and flux composition (rosin resin, activator, solvent, etc.) kneaded into a paste (see Patent Document 1). In recent years, in consideration of environmental issues, there has been a demand for solder compositions that are halogen-free, with reduced halogen content, or that contain no halogen at all. In addition, from the viewpoint of enabling soldering at lower temperatures, solder alloys containing bismuth, such as Sn-Bi, are used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5887330 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because bismuth (Bi) and indium (In) are easily oxidized, when a solder alloy such as a Sn-Bi system is used, it becomes difficult to remove the oxide film from the solder powder, resulting in the problem of solder balls being generated.

[0005] An object of the present invention is to provide a flux composition, a solder composition, and an electronic substrate that can sufficiently suppress the occurrence of solder balls even when a solder alloy containing bismuth or indium is used. [Means for solving the problem]

[0006] According to the present invention, there are provided a flux composition, a solder composition, and an electronic board as described below. [1] A composition comprising (A) a resin, (B) an activator, and (C) an antioxidant; The component (C) contains (C1) a compound having a carbon-carbon double bond and a hindered phenol structure in one molecule. Flux composition. [2] The flux composition according to [1], The carbon-carbon double bond of the component (C1) is an acryloyl group. Flux composition. [3] The flux composition according to [1] or [2], Further containing (D) a thixotropic agent, Flux composition. [4] A flux composition according to any one of [1] to [3] and (E) a solder powder. Solder composition. [5] The solder composition according to [4], The alloy system of the component (E) is any one of Sn-Bi system, Sn-Ag-Bi system, Sn-Ag-Sb-Bi system, Sn-In system, Sn-Bi-Sb-In system, Sn-Bi-Sb-In-Ni-Co system, and Sn-Bi-Sb-Cu-In-Ni-Co system; Solder composition. [6] The solder composition according to [4], The alloy composition of the component (D) is any one of Sn-57Bi-1Ag, Sn-58Bi, Sn-35Bi-1Ag, Sn-45Bi-1.5Sb-0.5Ag, Sn-50Bi-1Sb-0.5In, Sn-50Bi-1Sb-0.5In-0.05Ni-0.1Co, and Sn-50Bi-1Sb-2Cu-0.5In-0.05Ni-0.1Co; Solder composition. [7] A soldered portion using the solder composition according to any one of [4] to [6]. Electronic board. Effect of the Invention

[0007] According to one aspect of the present invention, it is possible to provide a flux composition, a solder composition, and an electronic substrate that can sufficiently suppress the occurrence of solder balls even when a solder alloy containing bismuth or indium is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Flux composition] First, the flux composition according to the present embodiment will be described. The flux composition according to the present embodiment contains the components other than the solder powder in the solder composition, namely (A) resin, (B) activator, and (C) antioxidant, which will be described below. In addition, the component (C) contains (C1) a compound having a carbon-carbon double bond and a hindered phenol structure in one molecule.

[0009] [Component (A)] Examples of the (A) resin used in this embodiment include rosin resin, acrylic resin, epoxy resin, and phenol resin. These may be used alone or in combination of two or more. Among these, rosin resin or acrylic resin is preferred from the viewpoint of viscosity stability. Examples of the rosin-based resin include rosins and rosin-based modified resins. Examples of the rosins include gum rosin, wood rosin, and tall oil rosin. Examples of the rosin-based modified resin include disproportionated rosin, polymerized rosin, hydrogenated rosin, and derivatives thereof. Examples of the hydrogenated rosin include fully hydrogenated rosin, partially hydrogenated rosin, and hydrogenated products of unsaturated organic acid-modified rosins (also called "hydrogenated acid-modified rosin"), which are modified rosins of unsaturated organic acids (aliphatic unsaturated monobasic acids such as (meth)acrylic acid, aliphatic unsaturated dibasic acids such as α,β-unsaturated carboxylic acids such as fumaric acid and maleic acid, unsaturated carboxylic acids having aromatic rings such as cinnamic acid, etc.). These rosin-based resins may be used alone or in combination of two or more. Among these rosin-based resins, it is preferable to use fully hydrogenated rosin and hydrogenated acid-modified rosin, and it is more preferable to use fully hydrogenated rosin and hydrogenated acid-modified rosin in combination. The acrylic resin is obtained by polymerizing at least one monomer such as acrylic acid, methacrylic acid, various esters of acrylic acid, various esters of methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride, esters of maleic acid, esters of maleic anhydride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl chloride, and vinyl acetate. The acrylic resin is useful in that it can prevent cracks from occurring in the flux residue even in an environment with a large temperature difference and a large thermal shock. Among these acrylic resins, acrylic resins obtained by polymerizing monomers containing methacrylic acid and a monomer having an alkyl group with 2 to 6 carbon atoms, and further acrylic resins obtained by polymerizing monomers containing methacrylic acid and a monomer having an alkyl group with 2 carbon atoms are preferred. Such acrylic resins are preferred in that they suppress the stickiness of the flux residue (flux solidified product) formed and have a good crack suppression effect.

[0010] The amount of the (A) component is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 60% by mass or less, and particularly preferably 40% by mass or more and 50% by mass or less, based on 100% by mass of the flux composition. If the amount of the (A) component is more than the lower limit, the oxidation of the copper foil surface of the soldering land is prevented, making the surface more easily wetted with molten solder, so that the so-called solderability can be improved and solder balls can be sufficiently suppressed. Also, if the amount of the (A) component is less than the upper limit, the amount of flux residue can be sufficiently suppressed.

[0011] [(B) Component] The (B) activator used in this embodiment preferably contains (B1) a compound having a quinoline skeleton. This (B1) component has the effect of improving the effect of suppressing solder balls. This (B1) component preferably has one or more hydroxyl groups in one molecule. The component (B1) is preferably a compound represented by the following general formula (1).

[0012] [ka]

[0013] In the general formula (1), X 1 ~X 7 are independently hydrogen, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms; X 2 ~X 7 Any two of these may form a ring. X 1 It is particularly preferred that is hydrogen. X 2 ~X 7 is preferably hydrogen, a hydroxyl group, a methyl group, or a methoxy group, and more preferably hydrogen or a methyl group.

[0014] Examples of the (B1) component include 8-quinolinol, 2-methyl-8-quinolinol, and 5-methyl-8-quinolinol. These may be used alone or in combination of two or more.

[0015] The blending amount of the (B1) component is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 8% by mass, even more preferably 0.8% by mass to 5% by mass, and particularly preferably 1% by mass to 2.5% by mass. If the blending amount of the (B1) component is equal to or more than the lower limit, the effect of suppressing solder balls tends to be further improved, while if the blending amount is equal to or less than the upper limit, the insulating properties of the flux composition tend to be maintained.

[0016] It is preferable that the component (B) further contains an amine-based activator (B2), which has the effect of improving the effect of suppressing solder balls. Examples of the (B2) component include amine adducts, pyrrole compounds, imidazole compounds, and pyrazole compounds. These may be used alone or in combination of two or more. Among these, amine adducts or imidazole compounds are preferred from the viewpoint of solder melting properties. Examples of amine adducts include Fujicure FXR-1020, FXR-1030, FXR-1050, FXR-1080, and FXR-1081 (trade names, manufactured by T&K Toka Corporation), Amicure PN-23, MY-24, VDH, UDH, PN-31, and PN-40 (trade names, manufactured by Ajinomoto Fine-Techno Co., Ltd.), Adeka Hardener EH-2021, EH-4361S, EH-5046S, EH-3636AS (trade names, manufactured by ADEKA Corporation), and Cureduct P0505 (trade name, manufactured by Shikoku Chemical Industry Co., Ltd.). Examples of the imidazole compound include 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, and 1,2-dimethylimidazole. Among these, 2-ethyl-4-methylimidazole is preferred.

[0017] The blending amount of the (B2) component is preferably 0.1% by mass or more and 8% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, and particularly preferably 1% by mass or more and 3% by mass or less, based on 100% by mass of the flux composition. If the blending amount of the (B2) component is equal to or more than the lower limit, the effect of suppressing solder balls tends to be further improved, while if it is equal to or less than the upper limit, the insulating properties of the flux composition tends to be maintained.

[0018] It is preferable that the component (B) further contains an organic acid (B3), which has the effect of improving the effect of suppressing solder ball formation. Examples of the component (B3) include other organic acids in addition to monocarboxylic acids and dicarboxylic acids, etc. These may be used alone or in combination of two or more. Monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, tuberculostearic acid, arachidic acid, behenic acid, lignoceric acid, and glycolic acid. Examples of dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, fumaric acid, maleic acid, phenylsuccinic acid, tartaric acid, and diglycolic acid. Among these, from the viewpoint of activity, phenylsuccinic acid, glutaric acid, adipic acid, and suberic acid are preferred, and suberic acid is particularly preferred. Other organic acids include dimer acid, trimer acid, levulinic acid, lactic acid, acrylic acid, benzoic acid, salicylic acid, anisic acid, citric acid, and picolinic acid, etc. Among these, it is more preferable to use picolinic acid. As the component (B3), it is preferable to use a plurality of organic acids in combination.

[0019] The blending amount of the (B3) component is preferably 0.1% by mass to 12% by mass, more preferably 0.5% by mass to 10% by mass, and particularly preferably 1% by mass to 8% by mass, based on 100% by mass of the flux composition. If the blending amount of the (B3) component is equal to or more than the lower limit, the effect of suppressing solder balls tends to be further improved, while if the blending amount is equal to or less than the upper limit, the insulating properties of the flux composition tends to be maintained.

[0020] In addition to the components (B1) to (B3), the component (B) may further contain a halogen-based activator (B4) within a range that allows the object of the present invention to be achieved. Examples of the component (B4) include 2-iodobenzoic acid. However, from the viewpoint of halogen-free, the total amount of the components (B1) to (B3) is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on 100% by mass of the component (B).

[0021] The blending amount of the (B) component is preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less, and particularly preferably 3% by mass or more and 12% by mass or less, based on 100% by mass of the flux composition. If the blending amount of the (B) component is equal to or more than the lower limit, the activation action tends to be improved, whereas if the blending amount is equal to or less than the upper limit, the insulating property of the flux composition tends to be maintained.

[0022] [(C) component] The antioxidant (C) used in this embodiment must contain (C1) a compound having a carbon double bond and a hindered phenol structure in one molecule. This component (C1) can suppress the reoxidation of Bi or In. This component (C1) is preferably a compound having an acryloyl group and a hindered phenol structure in one molecule. Examples of the component (C1) include 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate and 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate. Examples of the component (C1) include compounds represented by the following structural formulas (2) and (3).

[0023] [ka]

[0024] The blending amount of the (C1) component is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 6% by mass, and particularly preferably 0.5% by mass to 4% by mass, based on 100% by mass of the flux composition. If the blending amount of the (C1) component is within the above range, the reoxidation of Bi or In can be more reliably suppressed.

[0025] From the standpoint of melting properties over a small area, the component (C) may further contain (C2) an antioxidant having a hindered phenol structure (excluding the component (C1)). Examples of the component (C2) include N,N'-bis{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl}hydrazine, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylene bis(oxyethylene)], and N,N'-bis[2-[2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethylcarbonyloxy]ethyl]oxamide.

[0026] When the (C2) component is used, from the viewpoints of inhibiting reoxidation and balancing solder melting properties and other physical properties, the mass ratio of the (C2) component to the (C1) component ((C2) / (C1)) is preferably 1 / 10 or more and 3 or less, more preferably 1 / 6 or more and 2 or less, and particularly preferably 1 / 4 or more and 1 or less.

[0027] In addition to the components (C1) and (C2), the component (C) may further contain another antioxidant (hereinafter referred to as the component (C3)) within the range that does not impair the effects of the present invention. However, the total amount of the components (C1) and (C2) is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more, based on 100% by mass of the component (C).

[0028] Examples of the component (C3) include sulfur compounds (such as didodecyl 3,3'-thiodipropionate), benzotriazole compounds (such as 1,2,3-benzotriazole), and phosphite compounds.

[0029] The blending amount of the (C) component is preferably 1% by mass or more and 15% by mass or less, more preferably 2% by mass or more and 10% by mass or less, and particularly preferably 3% by mass or more and 6% by mass or less, based on 100% by mass of the flux composition. If the blending amount of the (C) component is within the above range, the occurrence of solder balls can be more reliably suppressed.

[0030] [(D) component] From the viewpoint of printability, etc., the flux composition according to this embodiment preferably further contains (D) a thixotropic agent. Examples of the thixotropic agent used here include hardened castor oil, amides, kaolin, colloidal silica, organic bentonite, and glass frit. These may be used alone or in combination of two or more.

[0031] The blending amount of the (D) component is preferably 1% by mass or more and 20% by mass or less, and more preferably 2% by mass or more and 12% by mass or less, based on 100% by mass of the flux composition. If the blending amount is less than the lower limit, thixotropy is not obtained and sagging tends to occur easily, whereas if the blending amount exceeds the upper limit, the thixotropy is too high and printing defects tend to occur easily.

[0032] [solvent] From the viewpoint of printability, the flux composition according to the present embodiment preferably further contains a solvent. As the solvent used here, a known solvent can be appropriately used. As such a solvent, it is preferable to use a solvent having a boiling point of 170° C. or more. In addition, a glycol-based solvent is preferable. Examples of such solvents include diethylene glycol, dipropylene glycol, triethylene glycol, hexylene glycol, hexyl diglycol, 1,5-pentanediol, methyl carbitol, butyl carbitol, 2-ethylhexyl diglycol (EHDG), octanediol, phenyl glycol, diethylene glycol monohexyl ether, tetraethylene glycol dimethyl ether, dibutyl maleic acid, etc. These solvents may be used alone or in combination of two or more.

[0033] When a solvent is used, the blending amount is preferably 10% by mass or more and 65% by mass or less, and more preferably 20% by mass or more and 50% by mass or less, based on 100% by mass of the flux composition. When the blending amount of the solvent is within the above range, the viscosity of the obtained solder composition can be appropriately adjusted to an appropriate range.

[0034] [Other ingredients] In addition to the (A), (B), and (C) components and the solvent, other additives and even other resins can be added to the flux composition used in this embodiment as necessary. Examples of other additives include antifoaming agents, modifiers, matting agents, and foaming agents. The amount of these additives is preferably 0.01% by mass or more and 5% by mass or less with respect to 100% by mass of the flux composition.

[0035] [Solder composition] Next, the solder composition according to the present embodiment will be described. The solder composition according to the present embodiment contains the flux composition according to the present embodiment described above and the solder powder (E) described below. The amount of the flux composition is preferably 5% by mass or more and 35% by mass or less, more preferably 7% by mass or more and 15% by mass or less, and particularly preferably 8% by mass or more and 12% by mass or less, relative to 100% by mass of the solder composition. When the amount of the flux composition is less than 5% by mass (when the amount of the solder powder exceeds 95% by mass), the flux composition as a binder is insufficient, so that it tends to be difficult to mix the flux composition and the solder powder. On the other hand, when the amount of the flux composition is more than 35% by mass (when the amount of the solder powder is less than 65% by mass), when the obtained solder composition is used, it tends to be difficult to form a sufficient solder joint.

[0036] The solder composition according to the present embodiment is a halogen-free or non-halogen type, and can sufficiently suppress the occurrence of solder balls even when a solder alloy containing bismuth is used. Furthermore, even if the solder composition is compatible with halogen-free printed wiring boards, it can suppress the occurrence of solder balls at the same level as when a halogen-based activator is used, so it can be particularly preferably used as a halogen-free or non-halogen type solder composition. The halogen-free solder composition preferably has a chlorine concentration of 900 ppm by mass or less (more preferably, 100 ppm by mass or less, particularly preferably, 0 ppm by mass), a bromine concentration of 900 ppm by mass or less (more preferably, 100 ppm by mass or less, particularly preferably, 0 ppm by mass), an iodine concentration of 900 ppm by mass or less (more preferably, 100 ppm by mass or less, particularly preferably, 0 ppm by mass), and a halogen concentration of 1500 ppm by mass or less (more preferably, 300 ppm by mass or less, particularly preferably, 0 ppm by mass). Examples of halogen include fluorine, chlorine, bromine, and iodine. The chlorine, bromine and halogen concentrations in the solder composition can be measured according to the method described in JEITA ET-7304A, or simply calculated from the components and their amounts in the solder composition.

[0037] [(E) component] The solder powder (E) used in this embodiment is preferably made of only lead-free solder powder, but may be lead-containing solder powder. The solder alloy in this solder powder preferably contains at least one selected from the group consisting of tin (Sn), copper (Cu), zinc (Zn), silver (Ag), antimony (Sb), lead (Pb), indium (In), bismuth (Bi), nickel (Ni), cobalt (Co) and germanium (Ge). The solder alloy in the solder powder is preferably an alloy mainly composed of tin. More preferably, the solder alloy contains at least one of bismuth and indium. Furthermore, the solder alloy may contain at least one of antimony, silver, copper, and nickel as an additive element. According to the flux composition of the present embodiment, even when a solder alloy containing an additive element that is easily oxidized, such as bismuth and indium, is used, the occurrence of solder balls can be suppressed. Here, lead-free solder powder refers to a powder of solder metal or alloy to which no lead is added. However, the presence of lead as an unavoidable impurity in the lead-free solder powder is permitted, but in this case, the amount of lead is preferably 300 ppm by mass or less.

[0038] Specific examples of alloy systems for lead-free solder powder include Sn-Ag-Cu systems, Sn-Cu systems, Sn-Ag systems, Sn-Bi systems, Sn-Ag-Bi systems, Sn-Ag-Sb-Bi systems, Sn-Ag-Cu-Bi systems, Sn-Ag-Cu-Ni systems, Sn-Ag-Cu-Bi-Sb systems, Sn-Ag-Bi-In systems, and Sn-Ag-Cu-Bi-In-Sb systems. The flux composition according to the present embodiment can sufficiently suppress the occurrence of solder balls even in the case of a solder alloy system such as Sn-Bi system. Therefore, when using the (D) component of a solder alloy system containing Bi, etc., the effect of the flux composition according to the present embodiment can be particularly exhibited. Specific solder alloy systems include Sn-Bi system, Sn-Ag-Bi system, Sn-Ag-Sb-Bi system, Sn-In system, Sn-Bi-Sb-In system, Sn-Bi-Sb-In system, Sn-Bi-Sb-In-Ni-Co system, and Sn-Bi-Sb-Cu-In-Ni-Co system. Among these alloy systems, Sn-Bi system, Sn-Ag-Bi system, or Sn-Ag-Sb-Bi system is preferable. Specific solder alloy compositions include Sn-57Bi-1Ag, Sn-58Bi, Sn-35Bi-1Ag, Sn-45Bi-1.5Sb-0.5Ag, Sn-50Bi-1Sb-0.5In, Sn-50Bi-1Sb-0.5In-0.05Ni-0.1Co, and Sn-50Bi-1Sb-2Cu-0.5In-0.05Ni-0.1Co. Among these alloy compositions, Sn-57Bi-1Ag, Sn-58Bi, Sn-35Bi-1Ag, and Sn-45Bi-1.5Sb-0.5Ag are preferred.

[0039] The average particle size of component (E) is usually 1 μm or more and 40 μm or less, but from the viewpoint of compatibility with electronic boards having narrow pitches of solder pads, it is more preferably 1 μm or more and 35 μm or less, even more preferably 2 μm or more and 35 μm or less, and particularly preferably 3 μm or more and 32 μm or less. The average particle size can be measured by a dynamic light scattering type particle size measuring device.

[0040] [Method of manufacturing solder composition] The solder composition of this embodiment can be produced by blending the above-described flux composition and the above-described (D) solder powder in the above-described predetermined ratio, and stirring and mixing them.

[0041] [Electronic board] Next, the electronic board according to the present embodiment will be described. The electronic board according to the present embodiment is characterized by having a soldered portion using the solder composition according to the present embodiment. The electronic board according to the present embodiment can be manufactured by mounting electronic components on an electronic board (such as a printed wiring board) using the solder composition. Examples of the coating device used here include a screen printer, a metal mask printer, a dispenser, and a jet dispenser. In addition, electronic components can be mounted on an electronic board by a reflow process in which electronic components are placed on the solder composition applied by an application device and heated under specified conditions in a reflow furnace to mount the electronic components on a printed wiring board.

[0042] In the reflow process, an electronic component is placed on the solder composition and heated in a reflow furnace under predetermined conditions. This reflow process allows a sufficient solder joint to be formed between the electronic component and the printed wiring board. As a result, the electronic component can be mounted on the printed wiring board. The reflow conditions may be appropriately set according to the melting point of the solder. For example, the preheat temperature is preferably 90°C or more and 130°C or less, more preferably 100°C or more and 120°C or less. The preheat time is preferably 40 seconds or more and 120 seconds or less, more preferably 60 seconds or more and 100 seconds or less. The peak temperature is preferably 160°C or more and 190°C or less, more preferably 180°C or more and 190°C or less. The holding time at a temperature of 140°C or more is preferably 30 seconds or more and 120 seconds or less, more preferably 80 seconds or more and 120 seconds or less.

[0043] Furthermore, the flux composition, the solder composition, and the electronic board according to the present embodiment are not limited to the above-described embodiment, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention. For example, in the electronic substrate, the printed wiring board and the electronic component are bonded by a reflow process, but the present invention is not limited thereto. For example, instead of the reflow process, the printed wiring board and the electronic component may be bonded by a process (laser heating process) of heating the solder composition using laser light. In this case, the laser light source is not particularly limited and can be appropriately adopted according to the wavelength that matches the absorption band of the metal. Examples of the laser light source include solid lasers (ruby, glass, YAG, etc.), semiconductor lasers (GaAs, InGaAsP, etc.), liquid lasers (dye, etc.), and gas lasers (He-Ne, Ar, CO2, excimer, etc.). EXAMPLES

[0044] The present invention will now be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. The materials used in the examples and comparative examples are shown below. (Component (A)) Rosin resin A: Acrylic acid modified hydrogenated rosin, product name "Pine Crystal KE-604", manufactured by Arakawa Chemical Industries Co., Ltd. Rosin resin B: Fully hydrogenated rosin, product name "Foral AX", manufactured by Rika Finetech Co., Ltd. ((B1) component) Quinoline Compounds: 8-Quinolinol ((B2) component) Amine-based surfactant: 2-ethyl-4-methylimidazole, product name "2E4MZ", Shikoku Chemical Industry Co., Ltd. (Component (B3)) Organic acid A: Picolinic acid Organic acid B: Glutaric acid ((B4) component) Halogen-based activator: 2-iodobenzoic acid ((C1) component) Antioxidant A: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, trade name "Sumilizer GS", manufactured by Sumitomo Chemical Co., Ltd. Antioxidant B: 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate, trade name "Sumilizer GM", manufactured by Sumitomo Chemical Co., Ltd. ((C2) component) Antioxidant C: N,N'-bis{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl}hydrazine, trade name "Irganox MD-1024", manufactured by BASF ((D) component) Thixotropic agent A: Product name "Slipax ZHH", manufactured by Nippon Kasei Co., Ltd. Thixotropic agent B: Trade name "Himako", manufactured by KF Trading Co., Ltd. (Other ingredients) Solvent: Diethylene glycol mono-2-ethylhexyl ether (2-ethylhexyl diglycol (EHDG), boiling point: 272°C), manufactured by Nippon Nyukazai Co., Ltd. ((E) component) Solder powder A: Alloy composition is Sn-57Bi-1Ag, particle size distribution is 20 to 38 μm Solder powder B: Alloy composition is Sn-58Bi, particle size distribution is 20~38μm

[0045] [Example 1] 23 mass% rosin-based resin A, 20 mass% rosin-based resin B, 1 mass% quinoline compound, 1.5 mass% amine-based activator, 1 mass% organic acid A, 5.5 mass% organic acid B, 0.1 mass% halogen-based activator, 37.9 mass% solvent, 3 mass% antioxidant A, 4.5 mass% thixotropic agent A, and 2.5 mass% thixotropic agent B were charged into a container and mixed using a planetary mixer to obtain a flux composition. Thereafter, 10.4% by mass of the obtained flux composition and 89.6% by mass of solder powder A (total 100% by mass) were placed in a container and mixed with a planetary mixer to prepare a solder composition.

[0046] [Examples 2 to 4] A solder composition was obtained in the same manner as in Example 1, except that the materials were mixed according to the composition shown in Table 1. [Comparative Example 1] A solder composition was obtained in the same manner as in Example 1, except that the materials were mixed according to the composition shown in Table 1.

[0047] <Evaluation of solder composition> The solder composition was evaluated (solder ball test, pin-to-pin ball test) by the following method. The results are shown in Table 1. (1) Solder ball test The solder ball test was carried out with reference to the description in IPC TM-650 2.4.43. Specifically, the solder composition was printed in a circular shape with a diameter of 6.5 mm on a ceramic substrate with a thickness of 0.6 mm to 0.8 mm using a metal screen to prepare a sample. The above sample was placed on a hot plate set at 180°C, melted, and then removed 5 seconds later, held horizontally, and cooled. The number and size of the solder balls in the solder were observed using a 20x microscope, and judged according to the following criteria. Note that "Preferred", "Acceptable", "Unacceptable; Clusters", and "Unacceptable" are in accordance with the evaluation criteria described in IPC TM-650 2.4.43. ◎: "Preferred", flux residue or almost no solder balls in the vicinity (only a few). ○: "Acceptable", solder balls are scattered in or around the flux residue, but the solder balls are not densely packed. ×: "Unacceptable Clusters", solder balls are densely packed in the flux residue. ××: "Unacceptable", solder balls were found continuously all around the flux residue. (2) Ball between pins On a board having 80 copper pads of 0.4 mm×3.0 mm spaced at 0.8 mm intervals, the solder composition was printed at a printing speed of 50 mm / sec and a printing pressure of 0.2 N using a metal mask having a corresponding pattern. Then, the solder composition was melted in a reflow furnace (manufactured by Tamura Manufacturing Co., Ltd.) and soldering was performed to prepare a test board. The test board was observed with a magnifying glass to measure the number of solder balls between the pins (initial number of balls between pins, unit: pieces / pin). The reflow conditions were a preheat temperature of 100 to 120° C. (about 80 seconds), a time at a temperature of 140° C. or higher for about 100 seconds, and a peak temperature of about 185° C. Next, continuous printing was performed for 12 hours under the same printing conditions as above, and then soldering was performed under the same reflow conditions as above to prepare a test board. This test board was observed with a magnifying glass and the number of solder balls between the pins (number of balls between pins after continuous printing, unit: balls / pin) was measured. Then, the increase in the number of balls between the pins due to continuous printing [(number of balls between the pins after continuous printing) - (initial number of balls between the pins)] was calculated.

[0048] [Table 1]

[0049] As is clear from the results shown in Table 1, it was confirmed that the solder compositions of the present invention (Examples 1 to 4) gave good results in all of the solder ball tests and inter-pin ball tests. Note that the solder compositions of Examples 1 to 4 contain a small amount of halogen-based activator, and are therefore halogen-free solder compositions. Therefore, it was confirmed that the solder composition of the present invention can sufficiently suppress the occurrence of solder balls even when a solder alloy containing bismuth or indium is used. [Industrial Applicability]

[0050] The flux composition and solder composition of the present invention can be suitably used as a technique for mounting electronic components on electronic substrates such as printed wiring boards of electronic devices.

Claims

1. (A) a resin, (B) an activator, and (C) an antioxidant; The component (C) contains (C1) a compound having a carbon-carbon double bond and a hindered phenol structure in one molecule. Flux composition.

2. 2. The flux composition according to claim 1, The carbon-carbon double bond of the component (C1) is an acryloyl group. Flux composition.

3. The flux composition according to claim 1 or 2, Further containing (D) a thixotropic agent, Flux composition.

4. A flux composition according to claim 1 or 2, and (E) a solder powder. Solder composition.

5. The solder composition according to claim 4, The alloy system of the component (E) is any one of Sn-Bi system, Sn-Ag-Bi system, Sn-Ag-Sb-Bi system, Sn-In system, Sn-Bi-Sb-In system, Sn-Bi-Sb-In-Ni-Co system, and Sn-Bi-Sb-Cu-In-Ni-Co system, Solder composition.

6. The solder composition according to claim 4, The alloy composition of the (D) component is any one of Sn-57Bi-1Ag, Sn-58Bi, Sn-35Bi-1Ag, Sn-45Bi-1.5Sb-0.5Ag, Sn-50Bi-1Sb-0.5In, Sn-50Bi-1Sb-0.5In-0.05Ni-0.1Co, and Sn-50Bi-1Sb-2Cu-0.5In-0.05Ni-0.1Co; Solder composition.

7. A soldered portion comprising the solder composition according to claim 4. Electronic board.

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